The effect of culture age and various cooling rates on the survival and regrowth of cryopreserved cell cultures of PAPAVER SOMNIFERUM L. is described. Survival and regrowth following cryopreservation, in liquid nitrogen, occurred only with 4 and 5 day old cultures. No regrowth was observed in 3 or 6 day old cultures. Cooling rate had a significant effect on survival following cryopreservation with an optimum cooling rate of 0.5 degrees C min (-1).